1. Field of the Invention
The present invention relates to a water purifying device, more particularly a domestic purifying device, and to the method carried out in such a device.
2. Description of the Prior Art
The water purifying devices of the prior art usually comprise a constant level tank having two chambers separated by a substantially vertical wall, in order to define an oxidation chamber and a decanting chamber. Used water comes into the oxidation chamber, wherein a pumping means mixes it, and whereafter flows into the decanting chamber when a new amount of used water is brought into the oxidation chamber. In the decanting chamber, muds deposit at the bottom of the chamber, wherefrom they could be brought back to the oxidation chamber through an opening set in the lower part of the decanting chamber. Clarified water flows out through an exhaust port at the upper part of the tank.
In such devices of the prior art, the decanting chamber is generally smaller than the oxidation chamber, for reasons of overall dimensions. When the tank is fed with a certain amount of used water, this tank being a constant level tank, the same amount of clarified water must leave the decanting chamber. If the amount of used water is bigger than the volume of cleaned water in the decanting chamber, there is a part of the evacuated water which is not enough decanted, i.e. an amount of the biological muds flows out, weakening the active water purifying material of the tank. After an intensive utilization period, the small quantity of biological muds remaining in such a tank is no more sufficient for the treatment of used water : on the first hand, used water is not conveniently cleaned, and on the other hand the tank turns stinking.
One way to avoid such drawbacks is to increase the dimensions of the oxidation chamber and of the decanting chamber, in order that they have an inner volume always greater than the volume of used water introduced during the peak hours. Such as increase of the overall dimensions presents major drawbacks with respect to the installation of the purifying device as well with respedt to the installation of the purifying device as well with respect to the necessary energy consumption to set in motion the mass of water in the oxidation chamber.
According to another embodiment of the prior art, there is provided a sole tank which receives used water and biological muds and which communicates with the atmospheric pressure. Products contained in the tank are regularly aerated, they decant during a long period of time, after what a pumping means discharges the purified water. Such a device also presents the drawback of making the water flow through a mechanical apparatus having movable parts, such as a pump.